Nanomaterials Research proposes to develop an extremely sensitive, low temperature, low cost, and miniaturized chemiresistive detector that can be mounted inside a respirator to warn users when toxic organic vapors are present inside the respirator. The sensor will alert the wearer when the respirator's filter cartridge has been consumed, when the respirator doesn't fit properly, or when the respirator has been compromised for any reason. Current methods of predicting filter breakthrough are inexact and inefficient, and an active end of service life indicator would provide a significant advance in worker safety. Nanomaterials Research demonstrated during the Phase I that it is feasible to use novel materials selection (including polymers and nano-scale ceramic powders) to overcome present limitations of solid state sensor technology including: high operating temperature (300-400 degrees C), significant power consumption (a result of the high operating temperature), poor reproducibility from one sensor to the next, and a lack of stability over time. The development of new and unique polymer and ceramic composite sensors has resulted in a stable, reproducible sensor that is responsive to a wide range of toxic VOCs (volatile organic compounds) at temperatures well below current state of the art. During the Phase II, these results will be extended to many more classes of organic compounds, and low cost packaging and electronic circuitry to power the sensor will be developed. The resulting sensor will be marketed to respirator manufacturers for integration into their products. Our preliminary work has already attracted the attention of a major respirator manufacturer who will provide expertise on regulatory and packaging issues associated with integrating this technology into a respirator.